One of the most important castles of the Foix county
Perched on a karstic spur at 978 metres altitude, dominating the Auzat-Vicdessos basin from the hamlet of Olbier, Montréal-de-Sos Castle was one of the most strategically important fortresses of the Foix county. Built in the late 12th century to assert comital authority over the upper Vicdessos valley, it commands an incomparable 360° view of the high valley. Access from the valley floor passes through natural caves fitted out as tunnels — a unique feature that continues to astonish visitors.
Sixteen years of archaeological excavation
Between 2001 and 2017, under the direction of historian Florence Guillot, the castle underwent exceptional archaeological excavations. The results are remarkable: a complete and intact stratigraphic sequence, 14th-century engraved slates unique in the region, and a better understanding of medieval Pyrenean defensive architecture. The finds are displayed at the Maison des Patrimoines in Auzat (le Barri), which remains an active cultural centre.
Medieval rock paintings
One of the most astonishing features of Montréal-de-Sos is the presence in the caves surrounding the summit of medieval paintings whose interpretation remains debated — possibly Cathar symbols, possibly shepherds' graffiti. The question remains open, adding a mysterious dimension to this already historically charged site.
The castle is freely and freely accessible all year round from the hamlet of Olbier, via a stone path of approximately 15 minutes including passage through two natural cave-tunnels. For information on guided tours occasionally organised by the Maison des Patrimoines d'Auzat, contact them directly.
What you will see in our 360° panoramas
Our 360° panoramas taken in 2013–2014 cover the entire site: the fortress ruins, the access cave-tunnels, the medieval rock paintings, and all panoramic viewpoints overlooking the upper Vicdessos, Auzat and the surrounding peaks. A complete virtual visit of this exceptional site, leaving nothing out.